1. The time needed to complete a math examination is bell-shaped with a mean of 120 minutes and a standard deviation of 15 minutes.

a) What percentage of students will complete the exam in 105 minutes or less?

%

b) Assume that the class has 190 students and that the examination period is 150 minutes in length. How many students do you expect will not be able to complete the exam in the allotted time? Round answer to the nearest whole number.

c) A student is classified as extremely "efficient" if the amount of time spent on the exam is the lowest 2.5% for the distribution. What is the upper limit for the time it takes an extremely "efficient" student to finish the exam?

2. The Acme Company manufactures widgets. The distribution of widget weights is bell-shaped. The widget weights have a mean of 61 ounces and a standard deviation of 10 ounces. Use the Standard Deviation Rule, also known as the Empirical Rule. a) 68% of the widget weights lie between and b) What percentage of the widget weights lie between 31 and 71 ounces? % c) What percentage of the widget weights lie below 81 ? % d) Determine how many of the 220 widgets that Acme company manufactured fall within the 95% range? Round to the nearest whole number.

3. The five number summary of a dataset was found to be:

-6, 3, 9, 15, 22

a) What is the IQR?

b) Find the lower limit (ie: an observation is considered an outlier if it is below this).

c) Find the upper limit (ie, an observation is considered an outlier if it is above this).

4.